This page contains instructions for carrying out common procedures on the website, and answers questions that new or inexperienced users are likely to ask.
In the model there is a single gas phase, an aqueous phase that contains dissolved inorganic ions and water-soluble organic compounds, inorganic and organic solids (where these have been defined for the organic constituents of the system), and a second liquid phase that contains hydrophobic organic compounds.
Organic compounds, depending on their properties, are able to partition between the two liquid phases and into the gas phase. They can also form solids.
See the model description for a detailed explanation of the capabilities of the model, including a diagram of the gas/liquid/solid system.
It's a simple, three step process. Starting from a problem input page for one of the inorganic models, first: press the "Manage Compounds" button to go to the Available Compounds page. Second, choose the organic compound you want from the drop-down list in section (1), and press "Add to system". Third, use the "Return to calculation' button to go back to the problem input page. You will find that an input box for the number of moles of organic compound has been added to the page, plus other options. You can now do your calculation.
There is a small set of "public" compounds (including several dicarboxylic acids) that can be selected from a drop-down box on the Available Compounds page. However, the system allows users to define the properties of compounds that they enter themselves, and this is expected to be the main way in which the model is used. See section 2 below for further details.
You can define organic compounds or surrogates that have exactly the thermodynamic properties that you want. Use the "Create compound" button on the Available Compounds page to go to a blank data entry form.
On this form you can specify molar mass, Henry's law constant or vapour pressure, solubility in water, dissociation constants, activity coefficient equations (if any), and which liquid phase(s) the compound can be present in. For further details, see the help information for the organic properties page.
Each compound you define is then automatically added to the inorganic systems in Models I-IV, and you will find boxes for organic compound amounts on the problem input pages.
You have three choices:
First, if the organic compounds that you want are in the public library (these are the ones that are always present in the drop-down box on the Available Compounds page) then first follow the instructions given in answer to question 2 in the section above.
Second, if you want to model systems that contain organic compound(s) with properties that you define, follow the instructions given in answer to question 3 in the section above to create the compound(s) and add them to your model system.
Third, if you want to do calculations using organic compounds that someone else has created, then obtain their library code and enter it in the box near the bottom of the Available Compounds page. This will add their "public" compounds to the list in the drop-down box from which you can select the ones you want.
After selecting and/or creating your compounds go to a problem input page for any of Models I-IV. The pages are automatically modified to include the organic compounds. Enter the numbers of moles of each one in exactly the same way you do the numbers of moles of inorganic ions.
There may also be some organic options for you to choose - such as the activity coefficient model, dissociation (or not) into ions, or limiting the compound(s) to occur only in a single liquid phase. Move your mouse pointer over the "help" box associated with each one of the options for an explanation of what it means.
The printed results of the model will look similar to those for inorganic systems, but with the extra organic species added. Amounts, concentrations, and activity coefficients of organic species in the hydrophobic liquid will be given, if it exists. Note that water and ions are not permitted to partition into this phase.
Use the "Create compound" button on the Available Compounds page to go to a blank data entry form.
On this form you can specify molar mass, Henry's law constant or vapour pressure, solubility in water, dissociation constants, activity coefficient equations (if any), and which liquid phase(s) the compound can be present in. For further details, see the help information for the organic properties page.
When you save the compound, using the button "Save the data" each compound you define is automatically added to the inorganic systems in Models I-IV, and you will find boxes for organic compound amounts present on the problem input pages.
You need to be registered with the site, and logged in. You will then find an option "Save to library" on the data entry page for organic compounds. If you select this option then the compound and its properties will be saved permanently on the E-AIM server. Next time you log in you will be able to select your compounds from the drop-down list on the Available Compounds page.
Yes, you need to obtain the library code of the other user(s). Enter it in the box near the bottom of the Available Compounds page. This will add the user's "public" compounds to the list in the drop-down box from which you can select the ones you want.
Yes, if you given them your library code (which is shown with your name near the top of the Available Compounds page every time you log in).
There are two important things to remember: first, the other users can only see the compounds in your library which you designated as "public" when you saved them. Second, users cannot alter any of the properties of these compounds in your library (though they can change them for temporary use in their sessions).
No, unless you give them your library code. If you give them your library code they will be able to see and use the compounds you have designated as public. However, only you can alter its contents.
The volatility of the compound expressed as a vapour pressure or Henry's law constant, its solubility in water with respect to the solid compound or hydrate, dissociation constants (if the compound is an acid), and how its activity coefficients in the liquid phase(s) are calculated. Users can specify whether the compound will partition between any aqueous and hydrophobic phases that may exist, or restrict them to a single phase.
A non-volatile, non-dissociating, water soluble or hydrophobic compound that obeys Raoult's law. You would enter the name and molar mass of the compound, specify which condensed phase it exist in (aqueous or hydrophobic), and accept the default settings for other properties.
Not yet. The simple expressions used to represent these effects are suitable only for relatively dilute solutions, and we also don't have a way of predicting the salt effect based on molecular structure. Because of this, activities in mixed inorganic/organic aqueous solutions are significantly more uncertain than those calculated for systems containing only inorganic electrolytes (for which the models are based on measurements), or mixtures of organic compounds.
(The command line version of the E-AIM code contains parameters for describing salt effects on dissolved organic compounds, and these parameters can be assigned by the user. Contact S. Clegg for further details.)
There are three methods. The first, and simplest, is to assume Raoult's law behaviour (mole fraction activity coefficients, reative to a reference state of the pure liquid, equal to unity). The second method, for compounds that are water-soluble, is a Redlich-Kister expansion for which the user must supply the fitted coefficients. Clegg and Seinfeld (J. Phys. Chem. A 110, 5692-5717, 2006) give exmaples of this equation applied to aqueous solutions of dicarboxylic acids. The third option, for compounds that can exist in either or both liquid phases, is UNIFAC. In this case the user must specify the group composition of the molecule. See the model description for details of all three approaches.
Go to the Login and Registration page and click on the Registration link. You will be guided through the process which takes only a couple of minutes to complete.
Links to the Login and Registration page can be found on both the E-AIM home page, and on the Available Compounds page.
Go to the Login and Registration page, and enter your username in the box provided, and you will be emailed your password.
Your username is your email address, the same one you used to receive your confirmation of registration. If you use several email addresses, and can't remember which one is your username, you can enter them and see whether they are recognised. Alternatively, please email the E-AIM administrator.
Yes, but you must have a different username (i.e., email address) for each one. Having two or more accounts can be useful if you which to share different sets of organic compounds that you create with different groups of people. For example, you might have one set of compounds you use with your research group, and a second set for a class of students.
You share the compounds that you have designated as "public" in your library by giving the other users your alphanumeric library code. This is displayed with your name near the top of the Available Compounds page each time you log in.